Zhang Yongxin, Yu Hongxian, Liu Jiamin, Guo Yao
College of Wildlife and Protected Area, Northeast Forestry University, No. 26 Hexing Road, Harbin 150040, China.
Heliyon. 2024 Feb 9;10(4):e25955. doi: 10.1016/j.heliyon.2024.e25955. eCollection 2024 Feb 29.
Majiagou River, a crucial urban river in Harbin, traverses densely populated areas including agricultural, suburban, and main urban areas, presenting highly intricate habitat characteristics. In recent years, urbanization has significantly intensified human interference, fundamentally reshaping the phytoplankton community. Understanding the response mechanism of phytoplankton to environmental factors is of paramount importance as they serve as primary producers in aquatic ecosystems. To investigate this, we established 25 sampling sites to analyze the phytoplankton community and 14 key physicochemical parameters, such as total phosphorus (TP) and total nitrogen (TN). Utilizing hierarchical clustering analysis (HCA) and One-way Analysis of Variance (ANOVA), we identified distinct river segments, revealing spatial distribution differences and environmental factor variations among phytoplankton species across segments. By adopting redundancy analysis (RDA), we pinpointed the primary environmental factors impacting phytoplankton communities and examined the correlation between phytoplankton and these factors to elucidate the driving mechanisms governing phytoplankton dynamics. The outcomes demonstrated that the phytoplankton community in Majiagou River was predominantly composed of Bacillariophyta and Chlorophyta, however, notable disparities in spatial distribution and species composition resulting from human interference were evident. Areas with intense human disturbance were dominated by diatoms and exhibited trends of homogenization and reduced biodiversity. RDA showed that pH, NH-N, NH-N, chemical oxygen demand (COD), and TP were key environmental factors influencing phytoplankton communities. We have confirmed that due to variations in environment conditions and different levels of human disturbance, there will be some differences in the critical limiting factors affecting phytoplankton. Our study offers valuable insights for governing urban rivers during the low-temperature period.
马家沟河是哈尔滨一条重要的城市河流，流经农业区、郊区和主城区等人口密集区域，呈现出高度复杂的栖息地特征。近年来，城市化显著加剧了人类干扰，从根本上重塑了浮游植物群落。由于浮游植物是水生生态系统中的初级生产者，了解其对环境因素的响应机制至关重要。为此，我们设立了25个采样点来分析浮游植物群落，并测定了总磷（TP）、总氮（TN）等14个关键理化参数。利用层次聚类分析（HCA）和单因素方差分析（ANOVA），我们识别出不同的河段，揭示了各河段浮游植物物种的空间分布差异和环境因子变化。通过冗余分析（RDA），我们确定了影响浮游植物群落的主要环境因素，并考察了浮游植物与这些因素之间的相关性，以阐明浮游植物动态变化的驱动机制。结果表明，马家沟河浮游植物群落以硅藻门和绿藻门为主，但受人类干扰导致的空间分布和物种组成存在显著差异。人类干扰强烈的区域以硅藻为主，呈现出同质化趋势且生物多样性降低。冗余分析表明，pH值、氨氮、化学需氧量（COD）和总磷是影响浮游植物群落的关键环境因素。我们证实，由于环境条件的变化和人类干扰程度的不同，影响浮游植物的关键限制因素会存在一定差异。我们的研究为低温期城市河流治理提供了有价值的见解。
